Wall Street Journal reporter Evan Gershkovich, arrested in Russia in March on espionage charges, was remanded in custody until Aug. 30 in Moscow on Tuesday, the state news agency RIA reported, citing the court.

The FSB security service arrested Gershkovich, a U.S. citizen, on March 29 in the Urals city of Yekaterinburg on charges that carry a possible 20-year prison sentence. It accused him of collecting state secrets about Russia's military industrial complex.

Gershkovich was initially remanded in pre-trial detention until May 29, and that period has now been extended for a further three months.

A reporter for the American news network CNN tweeted that Gershkovich's parents were at the Lefortovo court in Moscow for the hearing.

Gershkovich and the Journal both deny the espionage charges, which U.S. President Joe Biden called illegal, and the United States has officially deemed him "wrongfully detained".

The Kremlin has said that Gershkovich, the first U.S. journalist detained in Russia on espionage charges since the end of the Cold War, was caught "red-handed".

(Writing by Kevin Liffey; editing by Alex Richardson and Mark Heinrich)